Balanced heating of electro-optic device using active electrodes

Abstract

A system for heating electro-optic media comprises an electro-optic device comprising: a first substrate having first and second surfaces; a second substrate having third and fourth surfaces; a chamber defined between the opposed third surface of the second substrate and the second surface of the first substrate; electro-optic medium in chamber; a first electrode associated with second surface of first substrate; and a second electrode associated with third surface of second substrate; and a circuit in communication with first and second electrodes, comprising: a first EMF source capable of producing a first voltage; a second EMF source capable of producing a second voltage different from the first voltage; a plurality of switches configured to control the application of first and second voltages to the first and second electrodes; and a controller configured to control the switches, the first EMF source, and the second EMF source.

The invention claimed is: 
     
       1. A system for selectively heating electro-optic media comprising:
 an electro-optic (EO) device comprising:
 a first substrate having a first surface and a second surface; 
 a second substrate having a third surface and a fourth surface; 
 a chamber defined between opposed second surface of first substrate and third surface of second substrate; 
 an electro-optic medium disposed within the chamber; 
 a first thin film electrode associated with the second surface of the first substrate; and 
 a second thin film electrode associated with the third surface of the second substrate; and 
 
 a circuit in communication with the first and second thin film electrodes, comprising:
 a first busbar electrode associated with the first thin film electrode; 
 a second busbar electrode associated with the first thin film electrode; 
 a third busbar electrode associated with the second thin film electrode; 
 a fourth busbar electrode associated with the second thin film electrode; 
 a first EMF source capable of producing a first voltage and in communication with the second busbar and the third busbar. 
 
 
     
     
       2. The system of  claim 1 , wherein the circuit further comprises:
 a second EMF source in communication with the first busbar and the second busbar and capable of producing a second voltage different from the first voltage; 
 a third EMF source in communication with the third busbar and the fourth busbar and capable of producing a third voltage similar in magnitude to the first voltage; and 
 a plurality of switches configured to control the application of first, second and third voltages to the first and second thin film electrodes; and 
 wherein the system further comprises a controller in communication with the circuit and configured to control the switches, the first EMF source, the second EMF source, and the third EMF source. 
 
     
     
       3. The system of  claim 2 , further comprising a fourth EMF source in communication with the controller and the first busbar and the fourth busbar. 
     
     
       4. The system of  claim 3 , further comprising: 
       a dual output electrical transformer comprising at least a first and a second secondary windings inductively coupled to a primary winding, where terminals of the first secondary winding are in communication with the first and second busbars and terminals of the second secondary winding are in communication with the third and fourth busbars; and 
       a fifth EMF source capable of delivering an alternating current voltage to the primary winding of the dual output electrical transformer. 
     
     
       5. The system of  claim 1 , further comprising: 
       a heating power source; 
       a first amplifier in communication with the third busbar; 
       a second amplifier in communication with the second busbar; 
       a third amplifier in communication with the fourth busbar; 
       a fourth amplifier in communication with the first busbar; 
       an alternating current power source in communication with the first and second amplifiers; and 
       an inverter circuit comprising a fifth amplifier in communication with the alternating current power source; 
       wherein the first, second, third, and fourth amplifiers are in communication with the heating power source; 
       wherein the third and fourth amplifiers are in communication with an output of the inverter circuit. 
     
     
       6. The system of  claim 5 , further comprising a fourth EMF source in communication with the controller and the first busbar and the fourth busbar.